Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
Product Strengths
- SOtM hopes the sPA-1000 will be thought of as the 'S class of class D'
- Active power supply noise cancellation with high-precision power regulation
Product Considerations
- When operating, it may affect AM radio reception, requiring the user to set a switch to 'off'
- THD+N is 0.05%
Takeaway: The sPA-1000 is a bespoke amplifier aiming to erase prejudices against class D amplification, and it features active power supply noise cancellation
All
sPA-1000
reviews

Manufacturer details
- User interface: Operating indicator LED x1
- Unbalanced input: x1, Max input voltage 2Vrms, Input impedance > 10kΩ
- Balanced input: x1, Input impedance > 10kΩ
- Channels: 2 (Bridge tied load)
- Power output: 200W@4 ohm / channel
- Frequency response: 20 ~ 40kHz
- THD+N: 0.05% > @ 1W, 8Ω
- AC power input Voltage: 220Vac ~ 240Vac / 100Vac ~ 120Vac
- AC Frequency: 50Hz / 60Hz
- Current: 3A / 6A
- Operating temperature: +10 ~ +30℃
- Storage temperature: 0 ~ +40℃
- Operating & storage humidity: 10% ~ 90%
- Dimension: 360 x 84 x 255(mm)
- Weight: 7.5 kg
Since we designed the Class D amplifier module for the sPA-1000, which is not like most Class D amplifiers that use the ready-made modules by a few amplifier module companies, it means that the sPA-1000 is inherently different from others, and can outperform them.
In particular, the sPA-1000 uses power stabilization technology (pumping reducer technology) on the power circuit which removes the power pumping phenomenon – when playing music on the speaker, the electromotive force is generated and it changes the power voltage-, and with this special power circuit, the sound can become more natural and bring out more details. Most of all, you can play music with very precise low and mid-high ranges.
In addition, from the input stage to the speaker output stage, a fully balanced circuit has been applied to withstand the noise from inside and from outside the product. Such special tec...
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
- SOtM's products are known for their sleek, compact, and stylish aluminum enclosures, setting them apart from typical computer-like designs, and resembling attractive audio components.
- They use a Linux-based operating system (Vortexbox or Eunhasu OS) known for its audio playback capabilities, paired with well-established software like Logitech Media Server or Roon, offering a mature user experience.
Select products
sHP-100
- Positioning: A combined USB DAC and headphone amplifier designed for flexible connectivity in modest setups.
- Description: Offers diverse input options and quality digital-to-analog conversion with proven chips, ensuring clean sound in compact environments. Compared to the more specialized functions in the phono equalizer or flagship digital systems, it serves users needing versatile performance in smaller rooms on a moderate budget.
sPQ-100PS
- Positioning: A specialized phono equalizer aimed at optimizing analog vinyl playback.
- Description: Supports multiple EQ graphs and cartridge selections, allowing users to tailor its performance to different vinyl records with precise, natural tone reproduction. Compared to the digital processing in higher-end systems like the sMS-2000 or power amplification of the sPA-1000, it focuses on dedicated vinyl setups.
sPA-1000
- Positioning: A fully balanced Class D power amplifier suited for demanding audio systems.
- Description: Uses advanced power stabilization and balanced circuitry to achieve natural sound with precise control, delivering detailed performance in mid-to-large room environments. Compared to the compact functionality of the sHP-100 and the digital sophistication of the sMS-2000, it meets the needs of users looking for robust amplification with higher build quality.
sCLK-OCX10
- Positioning: A master clock generator developed for high-end digital audio systems.
- Description: Produces a pure 10MHz sine wave clock output with ultra-low phase noise and selectable impedance, thanks to its dedicated analog design refined over many years. Compared to devices focused on signal processing like the sMS-2000 or amplification like the sPA-1000, it serves audiophiles who need tight synchronization and precision.
sMS-2000
- Positioning: An integrated high-end digital audio system configured as the flagship for immersive musical experiences.
- Description: Brings together premium components including a dedicated USB host card, Ethernet interface, high-grade clock module, and custom power supply to deliver exceptional depth and clarity. Compared to the focused roles of the sPA-1000 and sCLK-OCX10, it offers comprehensive functionality and superior performance suitable for large, sophisticated systems.
Our take on the brand
Look inside the brand
Our interview with the brand
What are two key technological innovations or strong opinions that differ you from other brands?
First, we don’t just use advanced technologies like ultra-high-speed digital hardware, precision audio clocking, or noise filtering—we develop them ourselves with a deep understanding of how each element affects sound quality. For example, our proprietary power electronics for audio circuits and custom-designed oscillators play a critical role in delivering our distinctive sound.
Second, while many brands prioritize marketing, we invest heavily in R&D. This means our products may not always be the most widely advertised, but they are built on a solid foundation of innovation and long-term vision. Rather than making minor upgrades, we aim to create fundamentally better products with each release. That’s a philosophy that consistently earns us loyal users around the world.
What's your approach to customer support?
At SOtM, we take customer support seriously. Customers are encouraged to first contact their local dealer or distributor, as they are trained to handle most issues and can provide service in the customer’s native language. However, if further assistance is needed, customers are always welcome to reach out to us directly. When a customer experiences an issue, we aim to respond quickly, diagnose the problem accurately, and offer a solution that minimizes any disruption. We go above and beyond by offering firmware updates, personalized setup help, and sometimes even remote access support to ensure the best possible experience.
What are your favorite tracks for showcasing the strength of your products?
Some of our go-to pieces include:
- Stravinsky – The Firebird Suite (Finale): Great for dynamics and layering.
- Copland – Fanfare for the Common Man: Perfect for testing impact, timing, and space.
- Mahler – Symphony No. 2 "Resurrection": A true challenge for any system, with massive scale and emotional intensity.
We also enjoy film scores for their emotional engagement and wide frequency content. Ultimately, we choose tracks that are musically moving and technically revealing—regardless of genre.
What other products pair best with yours?
Since we produce everything from digital sources to amplifiers and cables—essentially all components except speakers—we typically use speakers from brands like Focal and Magico in our reference systems. All other components in the system are SOtM products, allowing us to demonstrate the full potential of our technology in a fully optimized environment.
Used
SOtM
What if you spend more?
The A35.8 is Primare’s most powerful and flexible multi-channel amplifier, designed to serve the needs of virtually any high-performance multi-channel system through its ability for each pair of channels to be bridged to mono for an incredible level of power delivery and system building options, including 1500 watts of total output in a fully bridged bi-amped stereo configuration. Shipping June 2022!
Our summary
Product Strengths
- The A35.8 provides eight channels of 'unimpeachable Class D power in a fairly compact and very flexible package'
- Flexible configuration options for power output to speakers are available, such as bi-amping and bridging
- Each stereo pair can be bridged separately to make four times 375 watts (8 Ohms) from the eight times 150 watts
- Fault-free sound quality
- High quality fit and finish
- The A35.8 offers flexible connectivity options
Product Considerations
- The 20-amp power inlet is the seldom-seen variety with three horizontal blades
- The speaker output posts are spaced too widely for dual-banana plugs
- Cabling can be tricky
- A high current power cord is needed
- Lower gain is present, though this doesn't necessarily need to be an issue
Comparisons (according to reviewers)
- Vs NAD M28, the A35.8 gets you one more channel and more versatility for a 10% price increase
- Vs Benchmark AHB2, the Benchmark presented a more neutral tonal balance and undistorted soundstage
- Vs NAD C 298 stereo amplifiers, the Primare seemed slightly more forward, often conveying an appealing liveliness
Takeaway: The A35.8 power amplifier is a flexible and versatile product worth considering for anyone seeking a high-quality multi-channel setup. Its ability to bridge channels offers many ways to configure your speaker system.
Video review
Our take on the brand
Our summary
Product Strengths
- The EAR 890 produces 70Wpc in stereo, and can be bridged to 140W in monoblock
- Neutral sound that gets out of the way and lets the user enjoy the music
- Complex and dense music textures are handled with ease, and dynamically demanding passages are sailed through
- Articulate midrange
- Detailed and realistic bass
Product Considerations
- Removing/installing tube cages is difficult and time-consuming
- The loudspeaker binding posts are positioned too close to the output transformers, making it hard to tighten them properly
- Some assembly work appeared amateurish, specifically the use of silicone in various locations, such as fastening chassis wires
- The amplifier can operate quite hot
- May not have as much bass impact compared to solid state amps
Comparisons (according to reviewers)
- The EAR 890 monoblocks achieve SET-like definition along with the authority and swagger necessary for most full-size speaker systems, when compared to Cary Audio 300B SET amps
- The EAR 890 is as textured as the top LAMM designs, but with noticeably better neutrality and more power
- The EAR 890 surpassed the deHavilland KE50As with a more articulate midrange, producing more color and separation in the microtones of instruments
Takeaway: The EAR 890 is easy to set up and sounds good with very little tweaking, making it easy to just sit back, relax, and enjoy the music. It's a good choice for people who want a tube amp that is both musical and powerful for their home listening experience.
Video review
Our take on the brand
Our summary
Product Strengths
- Delivers amazing quality of sound and detail
- Bulletproof amplification
- Has a rhythmically soulful sound with a tremendously rich and natural midrange
- The A51's bass is well-defined, extremely textured, and robust
- With 250 watts on tap, the Parasound A51 will power virtually anything
Product Considerations
- Due to its class A/AB design, the A51 does get a bit warm and should be installed in a properly ventilated space and/or rack
- The A51 is large and heavy, and is best moved and/or positioned by two people
Comparisons (according to reviewers)
- Compared to Rotel, the Rotel makes the M&K Sound system slightly bright with a bit of sibilance, while the Parasound is more neutral
- Compared to Acurus A250, the Parasound had tighter bass, which is probably attributed to a better damping factor
Takeaway: The Parasound Halo A51 is a high-performance amplifier with great sound quality, detail, and build quality, making it an excellent choice for audiophiles and home theater enthusiasts. Its ability to deliver power and control to speakers makes it a valuable addition to any high-end audio system.
Video review
Our take on the brand
The AGD “TEMPO” Stereo Amplifier is the new addition to our state-of-the-art Hi-End Power Amplifiers family. TEMPO is our first compact Stereo Amplifier utilizing the same unique technology of Gallium Nitride Power-Stage design already in use with all its Hi-End AGD siblings.
Our summary
Product Strengths
- GaN technology allows for efficient power usage, with 94% of energy being turned into sound
- Compact size challenges the notion that high-quality amps need to be large
- Design and packaging create pride of ownership
- It can be run in bridged mode to deliver 400 watts into one channel
- Stability and ability to handle complex impedance loads
Product Considerations
- The slight sonic signature may not be for everyone
- If truly outrageous amounts of power are needed to drive speakers, a second AGD Tempo amp might be needed to run in a bridged configuration
- High-frequency noise was discovered when XLR cables were not connected between them
- Power cords can make a large difference, the included power cord doesn't flatter the amp
- Some traditionalists may find it hard to accept that it's a Class-D amplifier
Comparisons (according to reviewers)
- Compared to Peachtree Audio GaN400, the AGD Tempo reports to have better overall specifications
- Compared to Parasound Halo A21+, the AGD Tempo is simply superior
- Compared to Bricasti M30 monoblock amplifiers, the level of which the most subtle detail exists approaches reference Bricasti M30 monoblock amplifiers
Takeaway: The AGD Productions Tempo is a cutting-edge amplifier that offers a new take on audiophile amplification and rivals more expensive amplifiers. It can drive speakers easily while being energy efficient.
Video review
Our take on the brand
What competes at this price?
Our Summary
Product Strengths
- The M23's build quality feels solid and elegant, with impressive small design details
- The sound is striking in its purity and clarity
- It offers up to three levels of gain, switchable on the back panel, to best fit the system
- It provides a clear sound without sounding hard
- It features Purifi Eigentakt Class D amplification, which provides virtually unmeasurable distortion levels
Product Considerations
- The bass is clean but may be perceived as a little on the cool side and not as 'wompy-sounding'
- The M23 is not a forgiving amplifier that makes everything sound sweet and wonderful—it's not for those seeking a soft and mellow sound
- Bridging with speakers below 5 or 6 ohms is not recommended, as the amp will current limit and potentially shut down
- The reviewer found ergonomical challenges using fancy speaker cables in bridged mode due to wide terminal spacing
- The capacitive touch power button can accidentally trigger
Comparisons (according to reviewers)
- Vs Bel Canto C6i: The M23 offered a layer of refinement and better reproduction of the recording space
- Vs Pass XA25: The M23 had more transparent sound and detail, especially in the treble and upper mids, but lacked the organic quality of the XA25
- Vs HiFi Rose RS 520: The M23 sounded cleaner and had better separation/depth, HiFi Rose seemed to have an EQ built-in, emphasizing midrange and bass
- Vs NAD C298: The M23 is more neutral, deals with decay more naturally, and has better casework, making it look high-end
- Vs Anthem M1 monoblock amplifiers: The M23 was slightly more transparent throughout the entire frequency range
- Vs Bryston 4B 3: The Bryston had more grunt but the M23 is more neutral
Takeaway: The NAD M23 is a powerful and precise amplifier that delivers clean and clear sound, making it a great choice for audiophiles who want to hear their music as accurately as possible. It is especially well-suited for those looking to build a high-end system around a quality preamp or DAC.
Video review
Our take on the brand
Our Summary
Product Strengths
- Delivers ample, clean, and dynamic power to all channels, ensuring speakers reach their full potential
- Designed by John Curl, featuring Class A/AB circuitry for a balance of warmth, richness, efficiency, and punch
- Pleasing sound for dialogue and music, with very high-quality and detail
- Versatile, suitable for both movies and music, with a low noise floor for quiet passages and great transparency—that doesn't color the sound
- Built to last, with high-quality internal components
- Signal-sensing power-on mode can be fussy and may require adjustment
Product Considerations
- Super heavy and large, potentially requiring rearranging a system or dedicated rack space
- Only available in anodized black
Comparisons (according to reviewers)
- The A52 Plus has bigger parts and bigger power than the Outlaw Model 5000, including balanced XLR connections
- A52 Plus is the 'teenager' compared to the elder Parasound A51
- Parasound A52+ sounds better, is more accurate, and more powerful than the Denon receiver's amplifier section
Takeaway: The Parasound A52+ Halo is a versatile and powerful amplifier that delivers clean, dynamic sound for both home theater and music systems, with a build quality designed to last. This is a worthy investment for audiophiles and home theater enthusiasts who seek high-quality audio performance.
Video review
Our take on the brand
Our Summary
Product Strengths
- Exceptionally transparent sound output quality
- Exceptionally powerful, capable of outputting 500W into a 4-Ohm load
- Delivers a remarkably clean, transparent sound with very little noise or distortion
- The amplifier's ability to reproduce bass is awe-inspiring and delivers deep, powerful bass without distortion
- Runs cool and weighs very little for its sound output, making it easy to move around
Product Considerations
- Options can be a little pricy, such as the 12v trigger and RCA inputs
- The Starkrimson Stereo Ultra may lead to further system upgrades
- Depending on your sources, the Starkrimson Stereo Ultra will play exactly what you feed it, good or bad, and if your source components are slow, the Starkrimson Stereo Ultra will not speed them up
- Power on only after all connections are properly made, including the power cord, analog inputs, and speaker outputs, and wait five minutes after powering it off before removing any of the connections
Comparisons (according to reviewers)
- Compared to the Krell S550i integrated amp, the Starkrimson Stereo Ultra showed a much faster and finer resolution of the upper frequencies of the human voice and a far greater ability to play more of the microdetails of a recording
Takeaway: The Starkrimson amplifier is well-built and provides a level of speed and transparency to hifi music that makes listening to music very fun. Its GaN modules can be upgraded and it is available in several configurations.
Video review
Our take on the brand
Our Summary
Product Strengths
- A lovely, lush sounding performance that's hard to dislike and sounds smooth but far from lifeless, delivering high levels of detail in a cohesive and musical manner
- A sympathetic performer, it prefers to play to its inferior partnering equipment's strengths than overly expose their weaknesses, as many hifi audio examples tend to do
- It can cater for a wide range of headphones and connections and it is a benchmark product that's highly recommended
- Zero musical flaws to report and is nearly perfect in execution
- A stunning design to the eye and ear, it is overall a wonderful addition for the perfectionist who wants the very best performance at home or even in the studio
Product Considerations
- The volume control operation lacks linearity, making it hard to make subtle changes in level
- No input selector, so one should only connect one type at once
- On some samples, the volume control is loose and wiggles in its chassis housing
- The octal AC socket is a bit of an odd choice, considering most users might prefer IEC
- The depth, snap and weight of the low end was dynamic and exciting on some recordings and less than stellar on others
Comparisons (according to reviewers)
- Vs Musical Fidelity M1 HPA—the MHA200 has a lush warmness to the music that brings strings to life in a way that makes the M1 HPA sound somewhat sterile in comparison
- Vs EAR Yoshino HP-4 reference—the MHA200 was a touch brighter than the reference, though only slightly
Takeaway: The MHA200 is an enjoyable product with a rich, balanced, and powerful sound, that's more forgiving than most rivals and can be enjoyed for years to come. This headphone amp is perfect for personal listening, design, and operation that will work its magic.
Video review
Our take on the brand
Our Summary
Product Strengths
- Excellent build quality
- Clean and clear sound delivery
- Wide and precise soundstage with astounding bass power that's remarkably tight and tuneful
- Speakers can sound as if they're coming from outside the room, creating a holographic soundstage
- The S300+ can power basically any speaker
Product Considerations
- Runs hot, especially in high bias mode
- Somewhat heightened noise floor that presents as a light 'hiss'
- Bright power LED can be distracting in a dark room
- High gain may not be suitable for high sensitivity speakers
- Lacks any kind of volume control
Comparisons (according to reviewers)
- Vs Jadis Orchestra Reference—the S300+ wins in clarity, soundstage, instrument separation, and distortion level
- Vs Burson Funk—the S300+ sounds far cleaner, more detailed, and has better dynamics, resolution, and transparency
- Vs Cyrus One Cast—the S300+ sounds far more controlled, more dynamic, and punchy; the bass is tighter; the treble is crisp and airy; and the midrange is sweeter and more vivid
Takeaway: The KECES S300+ is a well-built and powerful amplifier that delivers a clean, detailed, and engaging sound for a variety of speakers. It is worth a try for those seeking a top-performing amplifier.
Video review
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